Over a period of many years power wheelchairs have been developed to increase the independence and mobility of handicapped people. While many advances have been made in the development of power wheelchairs, many problems remain. For example, insertion and removal of batteries is quite difficult for a disabled person. Typically the batteries must be removed from either the back or the side of a wheelchair. Frequently batteries must be removed for transportation or service. The heavy battery terminal wires must be removed before a battery is removed and then must be reconnected when a new battery is inserted. The process for inserting and removing the batteries may thus be quite difficult for a user of the wheelchair who does not have the strength to lift the batteries or the manual dexterity to easily make electrical connections by hand. The electrical connection between the battery and the controller/motor of the wheelchair also comprises an exposed wire which could loosen, corrode, or snag while the wheelchair is in use, possibly disabling the wheelchair and stranding the occupant.
The batteries are sufficiently heavy that they significantly affect the center of gravity of a wheelchair. This is particularly true when the batteries are located behind the seat. In order to provide adequate stability, it has usually been necessary to move the rear wheels rearward to a position behind the seat and thereby increase the length of the wheelbase. This makes the wheels very difficult to reach for manual propulsion of the wheelchair by an occupant. In addition, the rear drive wheels for motor driven wheelchairs are made smaller than conventional 22-26 inch diameter wheelchair wheels. In addition to placing the rear wheels out of the reach of the occupant, the larger wheelbase means that the wheelchair is less maneuverable.
Even if the occupant could reach the rear wheels to self propel the wheelchair, there would be no way for the occupant to disconnect the wheels from the drive motors. Manual self-propulsion of a motorized wheelchair by an occupant has thus been completely impractical.
Many examples of battery-powered wheelchairs may be found on the market. One such battery-powered wheelchair is foldable and has two batteries supported under the seat of the wheelchair on a foldable baseplate. The two batteries of the wheelchair must be removed from the side of the wheelchair and they must be removed together, that is, one of the batteries cannot be removed by itself. Insertion and removal of the batteries also requires that the wires which make the electrical connection between the batteries and the motor must be connected by hand. Furthermore, the rear wheels of the wheelchair are small and are not designed for the occupant of the wheelchair to be able to reach out and propel the wheelchair by hand when the motor is not energized. Thus, the wheelchair can only be propelled by another person who must push the wheelchair when the motor is not energized.